This section provides background information related to the present disclosure, which is not necessarily prior art.
Motor vehicle heating, ventilation, and air cooling (HVAC) systems typically include an HVAC casing with an evaporator and a heater core housed therein. In a heating mode, airflow that has passed into the HVAC casing through the evaporator, which is often deactivated, is directed through the heater core by a temperature mixing door arranged in parallel to the heater core. In a cooling mode, the evaporator is activated and the control door is positioned such that cooled airflow that has passed through the evaporator is directed away from the heater core. A secondary temperature mixing door may be placed between the evaporator and the heater core so that in the cooling mode a positive airflow seal prevents airflow from entering the heater core chamber and becoming heated. To reduce costs, simplify operation, and increase operational reliance of the HVAC system, it would be desirable to eliminate the control door between the evaporator and the heater core.